Viper Fan Install


DML FAQ : HOWTO : Viper Fan Install


Just a little bit of disclaimer, let it be known that I am not an electronic engineer, I am a graphic artist (that's why the diagrams look the way they do). I laid out this wiring to help my own installation, I hope it helps others. Caution should be used when following these diagrams. I'd hate for anyone to fry there truck because I didn't warn them of this.

People are different, so upon requests I ended up making several wiring diagrams. I finished my wiring with only one minor problem, where I wanted to have 2 LEDs to show low and high speeds. For some reason, when power is applied to either the low or high terminals on the fan, voltage leaks back through the other wire from the motor causing both LEDs to light. For now I have omitted the high speed LED.

  1. Wiring Diagram v.4
    Uses Saab Temp switch and has an optional kill switch. This is basically the one I used with some modifications.
  2. Wiring Diagram v.5
    Includes switches for power-manual-auto settings and low-high speed selection. On the auto setting, like above it uses the Saab switch. This one is a real monster. I wouldn't suggest using this one, but someone asked.
  3. Wiring Diagram v.6
    Using a single heat range temperature switch for the high speed and the A/C clutch compressor relay for low speed. With optional kill switch.
  4. Wiring Diagram v.8
    My simplest diagram, and it offers the best automatic control of operating conditions. Less wiring and makes use of a readily available, single temperature sensor. This diagram has a little color in it to show the routing of the relays. It's simpler than the previous ones that I did. I think it actually makes use of the 2 speeds better. It uses a single temperature sensor like the Painless Wiring or the PermaCool. I've not included any lights or manual switches, though you could add those in.

Thanks, Bernd for the input and the actual Viper diagram.
Relay wiring


I ordered all of the small electrical components except the Saab temperature switch from Waytek Wire They did charge me an extra $5 small order charge, but they have some really cool components. Make sure your order exceeds $25 to avoid the charge. (these prices may not be current)

Part Number Part Description Qty Price Total
46551Circuit Breaker 50 Amp1$1.75$1.75
23541Circuit Breaker Boot Yellow1$0.53$0.53
75011Bosch Relays High Capacity3$3.07$9.22
75280Relay Connector3$0.73$2.19
46041Mini Fuse Holder1$3.00$3.00
31073Terminal for Relay Connector, 1/4", push-on, 14-16ga wire25$0.09$2.40

Saab Temperature Switch

Saab temp switch $17 each shipped
Order form
Message about the switch
The switch's thread is 22m x 1.5, the wrench size is 29mm.

Hose Fitting

I made up the hose fitting using a nut that I got from a local plumbing supply I took it to a radiator shop and had them weld it to a piece of 1 1/2 radiator tubing approx 5" long. $2.50 for the nut and $20 for the pipe and welding and the guy even painted it black for me. It looks similar to the one in this photo:
Saab tee fitting


For a 1998 (other years maybe different)

Fan layout
The blue is what was cut off the large red arrows identify those areas. The one arrow in the middle on the right side was a notch I had to make so the Trans cooler lines could pass through. The green arrows show the screws that I put in to hold an angle brace that I installed. To get it to go all the way across the top I removed the half circular area indicated by the arrow at the top. You can see the angle bracket peeking through at that spot.

The mounting brackets were fabricated from angle brackets that I got from Lowes. They mount the fan to the Dakotas factory locations.

This photo shows the clearance between the fan and the water pump.
Fan clearance

Y2Kota's 2000 Install Information


Contributed by: Bill Nissley
Last updated: Wed Aug 11 21:16:16 2004